The purpose of this shared instrument is to provide access to the most effective and modern DNA sequencing methodology for a number of different laboratories at The University of Texas M.D. Anderson Cancer Center. Laboratories in eight different departments have requested to participate in this grant proposal. They represent a total in excess of 1.9 million dollars in NIH supported research. Determination of DNA sequences has become an essential method in a large number of Cell Biology and Molecular Biology projects. A growing number of laboratories at The University of Texas M.D. Anderson Cancer Center are utilizing manual DNA sequencing techniques as part of their efforts to characterize cDNA and genomic clones. These projects include clones for transcription factors, oncoproteins, proteins related to development, differentiation cancer, membrance receptors etc. Other projects study the function of gene regulatory segments and other biologically important molecules by site specific mutagenesis. Still other projects seek to define the mutations occuring in the retinoblastoma gene of patients with various forms of neoplasms or in the Wilms' tumor gene in patients with such tumors. The availability. of an automated DNA sequencer will greatly facilitate and improve the research of many NIH supported laboratories at this Institution. It is estimated that during the first year of operation of this instrument the requests will be in excess of 500,000 nucleotide sequences. We anticipate an increasing demand on this type of instrument by funded investigators and by new faculty members. Mr. Dave Toman, A Senior Research Assistant in the laboratory of the P.I., with extensive experience in manual DNA sequencing, will perform all DNA sequencing reaction and perform all operations with the instrument. An Internal Committee will be established, the composition of which will be broadly representative of the different users of the DNA sequencing facility. The Committee will decide about priorities and evaluate the quality of the DNA sequences, and review the fee structure. We anticipate that initially, a fee of about $30 per sequencing run will be charged to the users.